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C. Leyrat, C. Ferrari, P.O. Lagage, E. Pantin (AIM Team, CEA Saclay/Univ. Paris 7)
Ring temperatures mainly depend on the local dynamics of particles and on the physical properties of their surface. Azimuthal temperature variations are expected in rings, due to the cooling of particles when crossing the planetary shadow, and to the heating by the central planet (Ferrari and Leyrat 2005). The amplitude and shape of these variations are specific of their thermal and rotational properties, i.e. their thermal inertia, their spin rate and orientation or their vertical excursions around the ring plane. We have observed the three main Saturn’s rings (A, B and C) at low phase angle (6 degrees), on May 2004 and April 2005 at the Very Large Telescope (ESO), using the new mid-infrared spectro-imager VISIR. Rings have been observed in the Q band (19.5 microns) with a resolution of only 0.6 arcsec, in imaging mode. Three low resolution spectra of the west ansa have also been obtained in the wavelength range 9-14 microns. First results of these observations at high spatial resolution will be presented and discussed. They will also be compared to observations performed during the same epoch, with the CIRS spectrometer onboard the CASSINI spacecraft, at larger phase angles (Ferrari et al, this DPS).
This work has been supported by the “Programme National de Planétologie”.
The author(s) of this abstract have provided an email address for comments about the abstract: leyratc@discovery.saclay.cea.fr
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.